It is disclosed in U.S. Pat. No. 3,547,671 that titanium tetrachloride can be oxidized in the presence of aluminum trichloride and phosphorous trichloride to give rutile titanium dioxide. The amount of AlCl.sub.3 was sufficient to form 2-4% Al.sub.2 O.sub.3 and the amount of PCl.sub.3 was sufficient to form from 0.5-3% P.sub.2 O.sub.5 based on the weight of TiO.sub.2 pigment formed. It is also disclosed that rutilization is impeded by PCl.sub.3 but that the effect of PCl.sub.3 may be compensated for by increasing the AlCl.sub.3.